Us Weekly reports that the split is "amicable."
In addition to their separate credits, the TV stars have appeared together on in "Blades of Glory," "Horton Hears a Who!" "Spring Breakdown," and more.
Arnett also guest starred on "Parks and Rec," as did Poehler on "Arrested Development."
Arnett and Poehler are both likely to appear at the Primetime Emmy Awards on Sunday, Sept. 23.
Poehler is nominated for lead comedy actress and in the comedy writing category for "Parks and Rec."
Arnett's role on "30 Rock" earned him a nomination for the outstanding comedy guest actor award.